Increasing solder hole-fill in a printed circuit board assembly

ABSTRACT

A method, apparatus, and computer program product for increasing solder hole-fill in a printed circuit board assembly (PCBA) are provided in the illustrative embodiments. In the PCBA comprising a Printed Circuit Board (PCB) and the device, a pin of a device is caused to move in a first direction, the pin occupying a hole in the PCB, the hole being filled to a first distance by a solder material. By causing the pin to move, the solder material is drawn into the hole up to a second distance that is greater than the first distance. The pin is allowed to move in a second direction, to return the pin to an initial position in the hole. Allowing the pin to move in the second direction keeps the solder material at a third distance, wherein the third distance is greater than the first distance in the hole.

TECHNICAL FIELD

The present invention relates generally to a method, system orapparatus, and computer program product for manufacturing printedcircuit board assemblies. More particularly, the present inventionrelates to a method, system or apparatus, and computer program productfor increasing solder hole-fill in a printed circuit board assembly.

BACKGROUND

A Printed Circuit Board (PCB, plural PCBs) is a platform on whichelectronic components or devices, such as resistors, capacitors,integrated circuit packages, transistors, thyristors, transducers,switches, and many other types of electronic and electrical components,(collectively referred to hereinafter as “device” or “devices”) arerested, arranged, and electrically connected to one another as one ormore circuits. A PCB with one or more devices configured thereon iscalled a Printed Circuit Board Assembly (PCBA, plural PCBAs).

PCBAs are common-place, and are found in almost anything that includessome electronic parts. In the simplest form, a PCB originates as a thinflat board with one side coated in a conductive material, typicallycopper. The devices participating in a circuit occupy one side of anexample single-sided PCB.

A circuit design is overlaid on the board to identify the locations ofthe various devices that will participate in a circuit that will beformed using the board. The positions of the devices identify thepositions of the connectors, leads, or terminals (collectively referredto hereinafter as “pin” or “pins) of the devices, e.g., the positions ofconnector pins of an integrated circuit, the positions of the leads of aresistor or capacitor, the terminals of a transistor, and the like. Theconductive paths of the circuit connecting those pins are marked andmasked on the conductive coating of the PCB.

The conductive coating is then etched, typically by using a chemicalprocess, which removes all conductive material except the masked areasof the conductive material. The positions of the pins are drilled asholes through the board either prior to the etching or after theetching.

A pin partially or fully passes through a conductive material platedhole, e.g., a Copper plated hole, such that the pin becomes accessiblefrom the side of the board opposite the side where the device ispositioned. The pin is soldered to a conductive path that remains on thePCB after etching. This conductive path typically comprises a drilledhole that is plated with a conductive material, such as, including butnot limited to Copper. This plating that is attached to the inner wallof the cylindrical hole will form a connection to inner conductivelayers and conductive circuit traces that are exposed inside the hole bythe drilling process. Further, this conductive structure is alsoconnected to conductive pads that are on the top and bottom side of thehole. These pads are connected during the plating process.

The solder material is conductive material, e.g., a tin-lead alloy orsilver, which is heated to a liquid state. The solder material oftenincludes a flux material that removes any oxidation of the conductivematerial or other debris in the holes that might prevent the soldermaterial from forming an acceptable electrically conducting path betweenthe pin and the conductive path.

During the PCBA assembly process, the liquid solder material, and anyflux material mixed therein, fills the conductively plated holesoccupied by pins. The solder material solidifies in the holes, formingelectrical connections between the pins in the holes and theirrespective conducting paths reaching or passing through the holepositions.

A variety of soldering techniques are used to solder the pins in theholes. Wave soldering is one example technique that causes a wave ofsolder material to rise on a side opposite the side where a device ispositioned, and into one or more conductively plated holes occupied by apin of the device. The solder material that rises into the holessolidifies in those holes forming electrical connections between thecorresponding pins and conductive paths. The wave can rise into one ormore holes occupied by a corresponding number of pins of one or moredevices at a time.

Double-sides and multi-layered PCBs are used in a similar manner. Forexample, in a double-sides PCB, devices can be positioned on both sidesof the PCB, conductive paths of the different or same circuits can beetched on both sides of the PCB, and solder can be applied from bothsides for connecting the devices on the opposite sides with theirrespective circuits. Any number of single-sides or double-sides PCBs canbe stacked to form multi-layered PCBs in a similar manner.

SUMMARY

The illustrative embodiments provide a method, system or apparatus, andcomputer program product for increasing solder hole-fill in a printedcircuit board assembly. An embodiment includes a method for increasingsolder hole-fill in a Printed Circuit Board Assembly (PCBA). Theembodiment causes, in the PCBA, a pin of a device to move in a firstdirection, the PCBA comprising a Printed Circuit Board (PCB) and thedevice, the pin occupying a hole in the PCB, the hole being filled to afirst distance by a solder material. The embodiment draws, responsive tocausing the pin to move, the solder material into the hole up to asecond distance, wherein the second distance is greater than the firstdistance. The embodiment allows the pin to move in a second direction,wherein the move in the second direction returns the pin to an initialposition in the hole, and wherein the allowing the pin to move in thesecond direction keeps the solder material at a third distance, whereinthe third distance is greater than the first distance in the hole.

Another embodiment includes a computer usable program product comprisinga computer readable storage device including computer usable code forincreasing solder hole-fill in a Printed Circuit Board Assembly (PCBA).The embodiment further includes computer usable code for causing, in thePCBA, a pin of a device to move in a first direction, the PCBAcomprising a Printed Circuit Board (PCB) and the device, the pinoccupying a hole in the PCB, the hole being filled to a first distanceby a solder material, the causing the pin to move resulting in drawingthe solder material into the hole up to a second distance, wherein thesecond distance is greater than the first distance. The embodimentfurther includes computer usable code for allowing the pin to move in asecond direction, wherein the move in the second direction returns thepin to an initial position in the hole, and wherein the allowing the pinto move in the second direction keeps the solder material at a thirddistance, wherein the third distance is greater than the first distancein the hole.

Another embodiment includes an apparatus for increasing solder hole-fillin a Printed Circuit Board Assembly (PCBA). The embodiment furtherincludes a first hardware component for causing, in the PCBA, a pin of adevice to move in a first direction, the PCBA comprising a PrintedCircuit Board (PCB) and the device, the pin occupying a hole in the PCB,the hole being filled to a first distance by a solder material, thecausing the pin to move resulting in drawing the solder material intothe hole up to a second distance, wherein the second distance is greaterthan the first distance. The embodiment further includes a secondhardware component for allowing the pin to move in a second direction,wherein the move in the second direction returns the pin to an initialposition in the hole, and wherein the allowing the pin to move in thesecond direction keeps the solder material at a third distance, whereinthe third distance is greater than the first distance in the hole.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further objectives and advantages thereof, willbest be understood by reference to the following detailed description ofthe illustrative embodiments when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 depicts a block diagram of a network of data processing systemsin which illustrative embodiments may be implemented;

FIG. 2 depicts a block diagram of a data processing system in whichillustrative embodiments may be implemented;

FIG. 3 depicts a block diagram of an example configuration to cause areciprocating movement for increasing solder hole-fill in a printedcircuit board assembly in accordance with an illustrative embodiment;and

FIG. 4 depicts block diagrams of several example apparatusconfigurations any of which can be used for increasing solder hole-fillin a printed circuit board assembly in accordance with an illustrativeembodiment.

DETAILED DESCRIPTION

The illustrative embodiments are described using single-sided PCBs andPCBAs only as examples and not to imply any limitation on theillustrative embodiments. An embodiment described herein can be adaptedfor use with double-sided or multi-layered PCBs and PCBAs in a similarmanner, and the same are contemplated within the scope of theillustrative embodiments. The illustrative embodiments are describedusing copper and certain solder materials only as examples and not toimply any limitation on the illustrative embodiments. An embodimentdescribed herein can be adapted for use with other conductive materialsand other solder materials in a similar manner, and the same arecontemplated within the scope of the illustrative embodiments.

The illustrative embodiments recognize that during the soldering processin a PCBA assembly process, the solder material often does not fill theholes in the PCB to a satisfactory level. For example, if the hole isexpected to be filled fully (hundred percent height threshold) such thatsoldering material reaches each opposite ends of the hole, the presentlyused soldering processes fail to achieve such solder material reach. Asanother example, if the hole is expected to be filled to a certainheight beginning from the side the solder material is applied (a heightthreshold), often, the presently used soldering processes fail toachieve such solder material height into the hole. The height thresholdcan be specified in percentage, ratio, relative height, absolute height,or in any other suitable manner within the scope of the illustrativeembodiments.

The illustrative embodiments recognize that several factors areresponsible for the solder material's failure to achieve a given heightthreshold for the holes in a PCB. For example, in some cases, the holesare plated with copper and are often connected to several ground orpower planes, which are also made of copper. These plating, grounding,power planes, and other structures are also thermally conducting, andtherefore add thermal mass to the PCB. Molten solder material has toremain in the molten state and flow for a period to reach a heightthreshold in a hole. However, this added thermal mass causes the soldermaterial to dissipate heat and solidify before reaching the heightthreshold.

One method to overcome this additional heat dissipation due to theadditional thermal mass is to increase the thermal energy of the moltensolder material. However, the illustrative embodiments recognize thatthis raises the temperature of the solder material, which can often haveundesirable effects on the devices in the PCBA, the PCB material, orboth.

Another factor responsible for the solder material's failure to achievea given height threshold for the holes in a PCB is the oxidation ofcopper used on the PCB. Oxidation prevents the solder material fromadequately wetting to the copper or other conductive material. The lackof adequate wetting impedes the flow of thermal energy to the copperstructure, thereby reducing flow of molten solder material. As thesolder material flows progressively farther into the hole, the soldermaterial encounters lower temperature copper that remains oxidized inthe hole. This lower temperature oxidized copper prematurely cools thesolder material to a state where the flow of the solder material isimpeded.

Another current solution used to address the oxidized copper problem isto reduce the amount of power and ground planes connected to the hole,and to change the plane connection structure geometry. The illustrativeembodiments recognize that although this technique reduces the thermalmass somewhat, the reduction is not always sufficient to achieve theheight threshold, e.g., the minimum fifty percent hole-fill as requiredby certain industry specifications.

An additional presently-used method is to use more aggressive solderflux chemicals. However, the illustrative embodiments recognize thatwhen no-clean fluxes are not adequate for this purpose, water solublefluxes have to be used, and such fluxes are often not compatible withother solder chemistries on the PCBA.

The illustrative embodiments used to describe the invention generallyaddress and solve the above-described problems and other problemsrelated to solder material failing to reach a given height in PCB holesduring PCBA assembly process. The illustrative embodiments provide amethod, system or apparatus, and computer program product for increasingsolder hole-fill in a printed circuit board assembly.

An embodiment causes a pin to move in a hole that is being filled withsolder material. Particularly, the embodiment causes the pin to move inthe hole to draw the solder material into the hole.

For example, assume that a PCB has a device occupying a side—the deviceside (e.g., a top side), has one or more holes drilled through the PCB,has one or more pins protruding from the device into the one or morecorresponding holes, and has solder material being applied to the one ormore holes from an opposite side—the solder side (e.g., a bottom side).The flow of the solder material in the hole is therefore from the solderside to the device side.

For a hole occupied by a pin, an embodiment causes the pin in the holeto move in the direction of the flow of the solder material and then inthe opposite direction of the flow, while the molten solder is flowinginto the hole. In other words, while the solder material is flowing intothe hole, the embodiment causes the pin to move away from the solder inthe hole for a certain amount of time or distance, then reverse thedirection of the movement of the pin in the hole and cause the pin tomove towards the solder material. Thus, the embodiment causes areciprocating movement of the pin along the longitudinal axis of thehole.

In some cases, the movement in the direction of the flow causes a mildvacuum to be created in the hole, drawing the solder farther into thehole as compared to when the solder flows without the pin movement. Insome other cases, the molten solder has adhered to a portion of the pinprior to the movement in the direction of the flow. The movement in thedirection of the flow causes the molten solder material to move with thepin in the direction of the movement due to adhesion, drawing the moltensolder farther into the hole as compared to when the solder flowswithout the pin movement. In some cases, the movement in the directionof the flow causes both the vacuum and the adhesion, drawing the moltensolder farther into the hole as compared to when the solder flowswithout the pin movement.

An embodiment repeats the reciprocating movement of the pin a number oftimes. For example, assume that a wave of solder material lasts 10second. One embodiment causes the reciprocating movement of the pin tooccur 1-to-4 times in the 10 second duration. Thus, the movement of thepin in the hole according to the illustrative embodiments is distinctfrom vibrating the pin at least because the frequency of thereciprocating movement is significantly less than typical vibratingfrequencies which are typically in the range of tens to hundreds orthousands of times per second, to wit, of higher order than the durationof the wave, e.g., of exponential order. Generally, the order of thefrequency of the reciprocating movement according to the illustrativeembodiments is of the order of the duration of the wave or less.Furthermore, most vibrations are side to side in contrast with thedirections of reciprocating movement described herein.

An embodiment can be configured to use any suitable mechanism to causethe pin to reciprocate relative to the hole. One example embodiment usesa heat-activated material to cause the reciprocating movement. Forexample, a heat-activated material, such as paraffin wax, contract uponsensing the heat of the molten solder in the wave, and expands when thewave subsides or a cooling effect is applied to the heat-activatedmaterial (or vice-versa).

Another example embodiment uses an electro-mechanical apparatus to causea similar reciprocating movement of the pin. For example, a pair ofelectromagnets attract when a current is applied, and separate when thecurrent is not applied or reversed. The timing of the current can besynchronized with the timing of the wave using any suitable techniquewithin the scope of the illustrative embodiments.

Another example embodiment uses an electrical, mechanical, orelectro-mechanical apparatus to cause a similar reciprocating movementof the pin. For example, a motor, e.g., a stepper motor, can beconfigured to turn a screw for a period or distance when a current isapplied, causing an implement coupled to an end of the screw to move inthe desired direction of the pin's reciprocating movement. The screwturns in the opposite direction when the current is not applied orreversed. The timing of the screw operation can be synchronized with thetiming of the wave using any suitable technique within the scope of theillustrative embodiments.

In some embodiments, an apparatus to cause the reciprocating movementincludes different mechanisms to cause the reciprocating movements. Forexample, one pin on a PCBA may be caused to move in the reciprocatingmovement using a heat-activated material or one type of apparatus, andanother pin on the same PCBA may be caused to move in the reciprocatingmovement using an electro-mechanical device or another type ofapparatus.

Furthermore, an apparatus to cause the reciprocating movement mayinclude different mechanisms to cause movements in different directions.For example, while a lifting apparatus using heat, current, ormechanical force may cause the movement away from the solder material, arelease mechanism or a disconnecting mechanism may cause the pin tobecome free from a force applied by, or disengage from, the liftingapparatus and move back in the other direction—towards the soldermaterial. For example, the move away from the solder material may becontrolled by the lifting apparatus (lifter), while the move towards thesolder material may be free fall under gravity or a controlled descendunder the control of a release mechanism (release). Various releasemechanisms can be fashioned using this disclosure, such as in a mannersimilar to but opposite of the lifting mechanisms described herein, andthe same are contemplated within the scope of the illustrativeembodiments.

These example manners of causing the reciprocating movement of the pinare not intended to be limiting on the illustrative embodiments. Fromthis disclosure, those of ordinary skill in the art will be able toconceive other manners of causing the reciprocating movements, and thesame are contemplated within the scope of the illustrative embodiments.

Regardless of how caused, the apparatus to cause the reciprocatingmovement is mechanically coupled with the pin that is to be moved in thereciprocating movement. For example, in one example embodiment, theapparatus to cause the reciprocating movement is coupled with orattached to the device whose pin is to be moved in the reciprocatingmovement. Such an example configuration causes the entire device,including one or more pins attached to the device, to move in one orboth of the directions of the reciprocating movement.

In another example embodiment, the apparatus to cause the reciprocatingmovement is coupled with or attached to the PCB, with another apparatusmaintaining the devices of the PCBA stationary, causing a relativemovement between the PCB and the devices. Such an example configurationcauses the relative movement of the PCB to occur in one or both of thedirections of the reciprocating movement, causing the hole to moverelative to a stationary pin, with a similar result.

Generally, an apparatus to cause the reciprocating movement according toan embodiment, such as a lifter, a release, or a combination thereof,can be coupled with a pin of a device, multiple pins of a device, adevice, multiple devices, a portion of a PCB, the entire PCB, or somecombination thereof.

The illustrative embodiments are described with respect to certain PCBs,devices, pins, holes, movements, directions, sides of PCBs, materials,temperatures, states of materials, frequencies, distances, periods,thresholds, apparatus and their principles of operations, couplings,logic, rules, policies, algorithms, data processing systems,environments, components, and applications only as examples. Anyspecific manifestations of such artifacts are not intended to belimiting to the invention. Any suitable manifestation of data processingsystems, environments, components, and applications can be selectedwithin the scope of the illustrative embodiments.

Furthermore, the illustrative embodiments may be implemented withrespect to any type of data, data source, or access to a data sourceover a data network. Any type of data storage device may provide thedata to an embodiment of the invention, either locally at a dataprocessing system or over a data network, within the scope of theinvention.

The illustrative embodiments are described using specific code, designs,architectures, protocols, layouts, schematics, and tools only asexamples and are not limiting to the illustrative embodiments.Furthermore, the illustrative embodiments are described in someinstances using particular software, tools, and data processingenvironments only as an example for the clarity of the description. Theillustrative embodiments may be used in conjunction with othercomparable or similarly purposed structures, systems, applications, orarchitectures. An illustrative embodiment may be implemented inhardware, software, or a combination thereof.

The examples in this disclosure are used only for the clarity of thedescription and are not limiting to the illustrative embodiments.Additional data, operations, actions, tasks, activities, andmanipulations will be conceivable from this disclosure and the same arecontemplated within the scope of the illustrative embodiments.

Any advantages listed herein are only examples and are not intended tobe limiting to the illustrative embodiments. Additional or differentadvantages may be realized by specific illustrative embodiments.Furthermore, a particular illustrative embodiment may have some, all, ornone of the advantages listed above.

With reference to FIG. 1, this figure depicts a block diagram of aconfiguration where increasing solder hole-fill in a printed circuitboard assembly can be accomplished in accordance with an illustrativeembodiment. PCB 102 comprises one or more holes 104. One or more pins106 of device 108 occupy the one or more holes 104. An instance of hole104 need not necessarily be occupied by any pin, but when occupied, isoccupied by one instance of pin 106.

Only for the purposes of the clarity of the description and withoutimplying any limitation thereto, assume that wave soldering method isused to solder pins 106 in holes 104. Solder wave 110 comprises moltensolder material. Wave 110 rises as depicted to flow the molten soldermaterial into some holes in PCB 102. For example, the example depictionof FIG. 1 shows wave 110 causing the solder material to reach holes 104but not hole 112.

As recognized by the illustrative embodiments, various factors cause thesolder material, such as the solder material in wave 110, to not reach aheight threshold in holes 104. An embodiment described herein can beused to cause the solder material, e.g., the solder material in wave 110to reach higher or farther into holes 104 than depicted in FIG. 1.

With reference to FIG. 2, this figure depicts a block diagram of aconfiguration for increasing solder hole-fill in a printed circuit boardassembly in accordance with an illustrative embodiment. PCB 202 is anexample portion of PCB 102 in FIG. 1. Hole 204 is an example of hole 104in FIG. 1. Pin 206 is an example of pin 106 in FIG. 1. Device 208 is anexample portion of device 108 in FIG. 1.

A “Before” view is shown on the left side of the depiction of FIG. 2.The “Before” view shows a hole-fill condition prior to using anembodiment. In the “before” view, solder material 210 rises from examplesolder wave 110 of FIG. 1 into hole 206. Solder material 210 rises toheight 212 as shown. Height 212 is less than a height thresholdspecified for PCB 202, hole 204, device 208, in a specification, or somecombination thereof.

An “After” view is shown on the right side of the depiction of FIG. 2.The “After” view shows a hole-fill increase by using an embodiment. Inthe “before” view, an embodiment, such as an embodiment using a lifterapparatus described elsewhere in the disclosure, causes device 208 to bemoved in direction 214 relative to PCB 202. The movement in direction214 causes pin 206 to move by distance 216 as one part of thereciprocating movement described elsewhere in the disclosure.

The movement of pin 206 by distance 216 draws solder material 210farther into hole 204 by additional distance 218. Additional distance218 is in addition to distance 212 filled in the “Before” view. Soldermaterial 210 upon reaching a total height of distance 212 plus distance218 in hole 204, meets or exceeds the height threshold.

At a suitable time, while solder material 210 is still in a moltenstate, an embodiment causes pin 206 to move in a direction opposite todirection 214, such as by changing a direction of operation of thelifter apparatus that was used for movement in direction 214, or byemploying a release apparatus. Movement of pin 206 in a directionopposite to direction 214 does not cause solder material 210 to returnto height 212. Solder material 210 either remains at distance 212 plusdistance 218 in hole 204, or at some distance in addition to distance212, such that the height threshold remains met or exceeded when pin 206returns to the position depicted in the “Before” view.

An embodiment can optionally repeat the reciprocating movement of pin206 in the above described manner any number of times. For example, insome cases, repeated reciprocating movements of pin 206 in the mannerdescribed above may be useful to draw solder material 210 farther thandistance 212 plus distance 218 into hole 204.

With reference to FIG. 3, this figure depicts a block diagram of anexample configuration to cause a reciprocating movement for increasingsolder hole-fill in a printed circuit board assembly in accordance withan illustrative embodiment. Pins 306 of device 308 are examples of pin206 of device 208, respectively, in FIG. 2. The reciprocating movementof pin 306 comprises movement in direction 314 and 318, alternatingbetween directions 314 and 318.

Lifter 324 comprises an apparatus to cause a movement in direction 314of pin 306. Lifter 324 can be implemented using any suitable mechanismto cause the movement in direction 314, including, but not limited tothe example mechanisms described in this disclosure. Only as an example,lifter 324 is depicted as employing a heat-activated material as such amechanism.

Only as an example, lifter 324 is coupled with device 308 via coupler326. Without departing the scope of the illustrative embodiments,coupler 326 can be implemented in any suitable manner to provide amechanical coupling for transferring a mechanical force from lifter 324to pin 306 to cause the movement of pin 306 in direction 314. Forexample, one example implementation (shown) of coupler 326 coupleslifter 324 with device 308. Another example implementation (not shown)of coupler 326 couples lifter 324 with one or more pins in pins 306.Another example implementation (not shown) of coupler 326 couples lifter324 with PCB 202 of FIG. 2 on which device 308 is positioned.

Release apparatus 328 comprises an apparatus to cause a movement indirection 318 of pin 306. Release apparatus 328 can be implemented usingany suitable mechanism to cause the movement in direction 318,including, but not limited to the example mechanisms described in thisdisclosure. Release apparatus 328 can be coupled in any suitable mannerwith lifter 324, coupler 326, or both.

For example, the coupling between release apparatus 328 and lifter 324,coupler 326, or both, may take the form including, but not limited to, amechanical mechanism to cause a movement in direction 318,electro-mechanical mechanism to cause a movement in direction 318, adetaching mechanism or other mechanism to cause a movement in direction318. In one embodiment, release mechanism 328 may be completely absent,causing lifter 324 or coupler 326 to cause the movement in direction 318upon the solidification of solder material 210 of FIG. 2, passing ofsolder wave 110 from below holes 104 in FIG. 1, otherwise sensing achange in a temperature in hole 204 in FIG. 2.

With reference to FIG. 4, this figure depicts block diagrams of severalexample apparatus configurations any of which can be used for increasingsolder hole-fill in a printed circuit board assembly in accordance withan illustrative embodiment. Any apparatus depicted in FIG. 4 can bedeployed in any suitable orientation, and not just the orientationdepicted in FIG. 4. Apparatus 402 is an example of a combination oflifter 324 and release 328 in FIG. 3.

Example apparatus 402 employs a head-activated mechanism that causescontraction 404 in the presence (or absence) of a certain amount of heatand expansion 406 in the absence (or presence) of the same or differentamount of heat. Contraction 404 and expansion 406 result in movement ofcoupler 408, which is an example of coupler 326 in FIG. 3. The movementof coupler 408 according to contraction 404 and expansion 406 causes apin, e.g., pin 306 in FIG. 3, to move in directions 314 and 318,respectively.

Apparatus 422 is another example of a combination of lifter 324 andrelease 328 in FIG. 3. Example apparatus 422 employs anelectro-mechanical mechanism that causes attraction 424, e.g., magneticattraction, in the presence (or direction) of a certain amount ofelectrical current in lead 428. The electro-mechanical mechanism causesseparation 426, e.g., non-magnetism or magnetic repulsion, in theabsence (or reversed direction) of the same or different current in lead428. Attraction 424 and separation 426 result in movement of coupler430, which is an example of coupler 326 in FIG. 3. The movement ofcoupler 430 according to attraction 424 and separation 426 causes a pin,e.g., pin 306 in FIG. 3, to move in directions 314 and 318,respectively.

In one embodiment, controller 432 is usable to change a direction of thecurrent in lead 428. In another embodiment, controller 432 is usable toadjust a frequency of current reversal, which causes a frequency ofreciprocation in the reciprocating movement of the pin coupled tocoupler 430. In some circumstances, the operation of controller 432 canbe viewed as a release operation for apparatus 422, as describedelsewhere in this disclosure.

Apparatus 442 is another example of a combination of lifter 324 andrelease 328 in FIG. 3. Example apparatus 442 employs anelectro-mechanical mechanism that causes travel 444, e.g., travel duringscrew tightening, in the presence (or direction) of a certain amount ofelectrical current in lead 448. The electro-mechanical mechanism causestravel 446, e.g., travel during screw loosening, in the absence (orreversed direction) of the same or different current in lead 448. Travel444 and travel 446 result in movement of coupler 450, which is anexample of coupler 326 in FIG. 3. The movement of coupler 450 accordingto travel 444 and travel 446 causes a pin, e.g., pin 306 in FIG. 3, tomove in directions 314 and 318, respectively.

In one embodiment, controller 452 is usable to change a direction of thecurrent in lead 448. In another embodiment, controller 452 is usable toadjust a frequency of current reversal and therefore travel reversal,which causes a frequency of reciprocation in the reciprocating movementof the pin coupled to coupler 450. In some circumstances, the operationof controller 452 can be viewed as a release operation for apparatus442, as described elsewhere in this disclosure.

In certain circumstances, instructions to cause an operation of a lifterapparatus, a release apparatus, or an apparatus that is a combination ofthe lifer and release apparatus, can be implemented in software, such asin computer usable program code. Such code can be executed using ageneral purpose computer, or another data processing system that arewell known for their usability in executing computer usable code orinstructions for a variety of purposes. For example, the computer usableprogram code or instruction can be stored in a computer usable storagedevice and executed by a processor to actuate a coupler or cause amovement as described herein.

Thus, a method, system or apparatus, and computer program product areprovided in the illustrative embodiments for dynamic risk assessmentbased product sampling. While the movements of a pin are described firstaway from and then towards the solder material, an embodiment can beadapted to first move the pin towards the solder material and then away,such as to increase the adhesion of the solder material to the pin,within the scope of the illustrative embodiments.

The described methods for drawing the solder material into a hole can beused separately or in combination. For example, another method tofacilitate the movement of the solder material to attain the thresholddistance into the hole according to an embodiment comprises pre-heatinga hole, a portion of the PCB or the entire PCB on the side towards whichthe solder material is to be drawn. For example, if the solder materialis applied by a wave on one side (e.g., bottom side) of the PCB, theopposite side (e.g., the top side) of the PCB can be pre-heated to asuitable temperature such that the temperature difference between thetemperature of the solder material and the temperature of the conductivelining in the hole is reduced when filling a hole.

Such an embodiment for pre-heating a hole, or all or a portion of a PCB,can be used alone or in conjunction with another method describedherein. For example, the pre-heating can be combined with thereciprocating movement of the pin in the hole can be advantageous incertain circumstances, such as to reduce the number of reciprocatingmovements of the pins, to increase the speed of soldering whileachieving the threshold distance of solder material reach into the PCBholes, or for other reasons.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

What is claimed is:
 1. A method for increasing solder hole-fill in aPrinted Circuit Board Assembly (PCBA), the method comprising: causing,in the PCBA, a pin of a device to move in a first direction, the PCBAcomprising a Printed Circuit Board (PCB) and the device, the pinoccupying a hole in the PCB, the hole being filled to a first distanceby a solder material; drawing, responsive to causing the pin to move,the solder material into the hole up to a second distance, wherein thesecond distance is greater than the first distance; and allowing the pinto move in a second direction, wherein the move in the second directionreturns the pin to an initial position in the hole, and wherein theallowing the pin to move in the second direction keeps the soldermaterial at a third distance, wherein the third distance is greater thanthe first distance in the hole.
 2. The method of claim 1, furthercomprising: repeating, the causing, the drawing, and the allowing anumber of times at a first frequency, wherein the repeating causes thesolder material to reach a threshold distance into the hole.
 3. Themethod of claim 1, further comprising: using a heat-activated mechanism,the heat activated mechanism causing the move in the first directionresponsive to detecting a first temperature, and the heat activatedmechanism allowing the move in the second direction responsive todetecting a second temperature.
 4. The method of claim 3, wherein thefirst temperature is a result of the solder material filling the hole ina filling operation, and wherein the second temperature is a result of acessation of the filling operation.
 5. The method of claim 1, furthercomprising: using an electro-mechanical mechanism, theelectro-mechanical mechanism causing the move in the first directionresponsive to a first current flow, and the electro-mechanical mechanismallowing the move in the second direction responsive to a second currentflow.
 6. The method of claim 3, wherein the second current flow is acessation of a flow of electrical current.
 7. The method of claim 3,wherein the first current flow is a flow of electrical current in afirst current flow direction and the second current flow is a flow ofthe electrical current in a second current flow direction.
 8. The methodof claim 1, wherein the allowing occurs while the solder materialremains in a molten state.
 9. The method of claim 1, wherein the thirddistance is equal to the second distance.
 10. The method of claim 1,wherein the third distance at least equals a threshold distance.
 11. Themethod of claim 1, wherein the causing the pin to move is responsive tothe first distance being less than a threshold distance.
 12. The methodof claim 1, wherein the move in the first direction comprises moving thepin away from the solder material.
 13. The method of claim 1, furthercomprising: heating a portion of the PCB to a first temperature, whereinthe first temperature is less than a temperature of the solder materialin a molten state, the portion of the PCB occupying a side of the PCBthat is opposite a second side of the PCB, the solder material beingapplied to the PCB on the second side.
 14. The method of claim 1, thedevice comprising a plurality of pins, the plurality of pins includingthe pin.
 15. The method of claim 1, wherein the causing the pin to movein the first direction moves the pin from the initial position of thepin in the hole to a first position of the pin in the hole.